1. Field of the Invention
The present invention relates to a switch structure, and to a chronograph mechanism and an electronic timepiece using the the switch structure.
2. Description of the Related Art
There is known a switch structure including a terminal plate equipped with a plate-like main body portion and a switch lever portion, wherein the switch lever portion is equipped with an arm portion which is connected to an outer peripheral edge portion of the plate-like main body portion at one side of a proximal end portion and bent with respect to the outer peripheral edge portion of the plate-like main body portion at the one side of the proximal end portion and which extends from the proximal end portion along the outer peripheral edge portion of the plate-like main body portion along a surface crossing an extension surface of the main body portion, and is equipped with a pressing force receiving portion at a distal end side thereof, and an elastic contact portion further extending from the pressing force receiving portion of the arm portion (JP-A-61-83991 (FIG. 11, etc.) (Patent Document 1)). Further, there is also known a chronograph mechanism in which a start/stop (chronograph coupling) button and a reset button (for zero-restoring) are formed so as to exert a pressing force to a distal end side end portion of a corresponding switch structure, wherein a time measuring operation of a chronograph indication hand is started or stopped by a chronograph coupling lever rotated in response to the depression of the start/stop button, and wherein the chronograph indication hand is zero-restored by a zero-restoring instruction holding lever rotated in response to the depression of the reset button. Further, there is also known an electronic timepiece equipped with such a switch structure.
In the switch structure of the chronograph mechanism of an electronic timepiece of this type, the arm portion of the switch lever portion is deflected by the pressing force applied to the pressing force receiving portion situated at the distal end side of the arm portion, so that the pressing force receiving portion at the distal end side of the arm portion is not only rocked within a plane substantially parallel to a main surface of the electronic timepiece, but it almost inevitably undergoes a displacement more or less differing according to its position in a direction perpendicular to the main surface of the electronic timepiece (in the thickness direction of the electronic timepiece), so that not only is there a fear of an unexpected deviation being generated between the displacement that the start/stop button and the reset button impart to the distal end side end portion of the switch structure and the displacement of a contact portion formed at the distal end portion of an extension end portion of the arm portion, but there is also a fear of the deviation causing a problem that is not negligible in the operation of the contact with a change in the structure in the thickness direction of the timepiece.
That is, as the start/stop button or the reset button is depressed, there is a fear of a deviation being generated between various rotating operations generated in mechanical levers constituting the mechanical portion of the chronograph mechanism and the electrical on/off operation of the contact in response to the depression of the start/stop button or the reset button.
Such a deviation is more or less inevitable in a switch structure having a three-dimensional structure as described above; not only is a design of a structure of the like in which such a deviation is taken into account is complicated, but it requires a design change if the button position is just more or less changed.